WO2019059674A1 - Method for monitoring downlink channel or downlink signal, and wireless device - Google Patents

Abstract

Disclosed in the present specification is a method for monitoring, by a wireless device, a downlink channel or a downlink signal. The method may comprise a step of receiving configuration information on a power saving signal. The power saving signal may be used to signal that the downlink channel or the downlink signal should be monitored subsequently. The configuration information may include configuration information on a skip occasion of the power saving signal. The method may comprise a step of monitoring the downlink channel or the downlink signal without monitoring the power saving signal during the skip occasion. At least one of the length and the position of the skip occasion may be determined depending on the configuration information of a discontinuous reception (DRX) cycle.

Description

Method for monitoring downlink channel or downlink signal and wireless device

The present invention relates to mobile communications.

The 3rd Generation Partnership Project (3GPP) long term evolution (LTE), an enhancement of Universal Mobile Telecommunications System (UMTS), is introduced as 3GPP release 8. 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in the downlink and single carrier-frequency division multiple access (SC-FDMA) in the uplink. MIMO (multiple input multiple output) with up to four antennas is adopted. Recently, the evolution of 3GPP LTE, 3GPP LTE-A (LTE-Advanced), has been commercialized.

In the LTE / LTE-A, a physical channel is divided into a physical downlink shared channel (PDSCH) and a physical downlink control channel (PDCCH), a physical uplink shared channel (PUSCH) .

On the other hand, recently, Internet of Things (IoT) communication has attracted attention. IoT refers to communications that do not involve human interaction. A discussion is beginning to be made to accommodate such IoT communications in a cellular-based LTE system.

However, since the existing LTE system has been designed for the purpose of supporting high-speed data communication, it has been regarded as an expensive communication method.

However, IoT communication can be widely used because of its characteristics.

Thus, there have been discussions to reduce bandwidth as part of cost reduction. This is called NB (narrow band) IoT.

A general UE performs blind decoding on a PDCCH in an on period according to DRX (Discontinuous Reception). However, the NB-IoT device may not transmit / receive data frequently because of its characteristics. Therefore, it is inefficient to frequently monitor the PDCCH in the on interval according to DRX.

Accordingly, the disclosure of the present specification aims at solving the above-mentioned problems.

Specifically, the disclosure of the present disclosure aims to provide a way to maximize the energy efficiency of NB-IoT devices.

In order to accomplish the foregoing objects, one disclosure of the present disclosure provides a method for a wireless device to monitor a downlink channel or a downlink signal. The method may include receiving configuration information for a power saving signal. The power save signal may be used to signal that the downlink channel or downlink signal should be monitored subsequently. The setting information may include setting information for a skip occasion of the power saving signal. The method may include monitoring the downlink channel or the downlink signal during the skip interval, without monitoring the power saving signal. At least one of the length and the position of the skip interval may be determined by setting information of a DRX (Discontinuous Reception) cycle.

One or more of the length and position of the skip interval may be determined based on N times the length of the DRX cycle.

The length of the skip interval may be expressed as: SFN (system frame number).

The setting information for the power saving signal may include information on an expiration timer.

The method may further include driving the expiration timer in an interval other than the skip interval.

The method may further include the step of monitoring the downlink channel or the downlink signal if the power saving signal is not received until the expiration timer expires in a period other than the skip period .

The expiration timer may be initiated in connection with the release of a radio resource control (RRC) connection.

The release of the RRC connection may be performed based on the reception of the downlink control channel or the downlink data channel.

The release of the RRC connection may be performed based on transmission of an uplink control channel or an uplink data channel.

The expiration timer may be driven based on SFN.

In order to accomplish the above object, one aspect of the present disclosure provides a radio apparatus for monitoring a downlink channel or a downlink signal. The wireless device includes a transmitting / receiving unit; And a processor for controlling the transmitter / receiver to receive setting information for the power saving signal. The power save signal may be used to signal that the downlink channel or downlink signal should be monitored subsequently.

The setting information may include setting information for a skip occasion of the power saving signal. The processor may monitor the downlink channel or the downlink signal during the skip interval, without monitoring the power saving signal. At least one of the length and the position of the skip interval may be determined by setting information of a DRX (Discontinuous Reception) cycle.

According to the disclosure of the present specification, the problems of the above-mentioned prior art are solved.

1 is a wireless communication system.

2 shows a structure of a radio frame according to FDD in 3GPP LTE.

3 shows a structure of a downlink sub-frame.

Figure 4 shows an example of a DRX cycle.

5A shows an example of IoT (Internet of Things) communication.

5B is an illustration of cell coverage expansion or augmentation for an IoT device.

5C is an exemplary diagram illustrating an example of transmitting a bundle of downlink channels.

6A and 6B are views showing examples of sub-bands in which IoT devices operate.

FIG. 7 shows an example of time resources that can be used for NB-IoT in M-frame units.

Figure 8 is another example illustrating time and frequency resources that may be used for NB IoT.

9 is a flowchart showing an example of utilizing a power saving signal (or WUS).

10 shows an example in which the base station and the NB-IoT device apply an expiration timer.

FIGS. 11A and 11B are diagrams illustrating an operation of the NB-IoT device in a skip interval according to Option 2-1 of the second disclosure. FIG.

12 is an exemplary diagram illustrating the operation of an NB-IoT device according to option 2-2 of the second disclosure;

13 is an exemplary diagram illustrating the operation of the NB-IoT device according to Option 3-1 of the third disclosure;

FIG. 14 is an exemplary diagram illustrating the operation of the NB-IoT device according to option 3-2 of the third disclosure; FIG.

15 is an exemplary view showing the operation of the NB-IoT device according to the fourth disclosure;

16 is an exemplary diagram illustrating the operation of an NB-IoT device according to the fifth disclosure;

17 is an exemplary view showing the operation of the NB-IoT device according to the eighth embodiment;

18 is an exemplary view showing the operation of the NB-IoT device according to the ninth embodiment;

19 is an exemplary view showing the operation of the NB-IoT device according to the tenth embodiment;

20 is an exemplary view showing the operation of the NB-IoT device according to the eleventh disclosure;

21 is a block diagram illustrating a wireless device and a base station in which the present disclosure is implemented.

22 is a detailed block diagram of the transceiver of the wireless device shown in FIG.

Hereinafter, it is described that the present invention is applied based on 3rd Generation Partnership Project (3GPP) 3GPP long term evolution (LTE) or 3GPP LTE-A (LTE-Advanced). This is merely an example, and the present invention can be applied to various wireless communication systems. Hereinafter, LTE includes LTE and / or LTE-A.

It is noted that the technical terms used herein are used only to describe specific embodiments and are not intended to limit the invention. It is also to be understood that the technical terms used herein are to be interpreted in a sense generally understood by a person skilled in the art to which the present invention belongs, Should not be construed to mean, or be interpreted in an excessively reduced sense. Further, when a technical term used herein is an erroneous technical term that does not accurately express the spirit of the present invention, it should be understood that technical terms that can be understood by a person skilled in the art are replaced. In addition, the general terms used in the present invention should be interpreted according to a predefined or prior context, and should not be construed as being excessively reduced.

Also, the singular forms "as used herein include plural referents unless the context clearly dictates otherwise. In the present application, the term " comprising " or " having ", etc. should not be construed as necessarily including the various elements or steps described in the specification, and some of the elements or portions thereof Or may further include additional components or steps.

Furthermore, terms including ordinals such as first, second, etc. used in this specification can be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

When an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, but other elements may be present in between. On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals refer to like or similar elements throughout the several views, and redundant description thereof will be omitted. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. It is to be noted that the accompanying drawings are only for the understanding of the present invention and should not be construed as limiting the scope of the present invention. The spirit of the present invention should be construed as extending to all modifications, equivalents, and alternatives in addition to the appended drawings.

The term base station, as used hereinafter, refers to a fixed station that typically communicates with a wireless device and includes an evolved-NodeB (eNodeB), an evolved-NodeB (eNB), a Base Transceiver System (BTS) Access Point).

Hereinafter, the term NB IoT device, which is a used term, may be fixed or mobile and may be a device, a wireless device, a terminal, a mobile station (MS), a user terminal (UT) terminal, a subscriber station (SS), a mobile terminal (MT), and the like.

1 is a wireless communication system.

1, the wireless communication system includes at least one base station (BS) 20. Each base station 20 provides a communication service to a specific geographical area (generally called a cell) 20a, 20b, 20c. The cell may again be divided into multiple regions (referred to as sectors).

A terminal usually belongs to one cell, and a cell to which the terminal belongs is called a serving cell. A base station providing a communication service to a serving cell is called a serving BS. Since the wireless communication system is a cellular system, there are other cells adjacent to the serving cell. Another cell adjacent to the serving cell is called a neighbor cell. A base station that provides communication services to neighbor cells is called a neighbor BS. The serving cell and the neighboring cell are relatively determined based on the terminal.

Hereinafter, the downlink refers to communication from the base station 20 to the terminal 10, and the uplink refers to communication from the terminal 10 to the base station 20. In the downlink, the transmitter may be part of the base station 20, and the receiver may be part of the terminal 10. In the uplink, the transmitter may be part of the terminal 10 and the receiver may be part of the base station 20.

Meanwhile, the wireless communication system can be roughly divided into a frequency division duplex (FDD) system and a time division duplex (TDD) system. According to the FDD scheme, uplink transmission and downlink transmission occupy different frequency bands. According to the TDD scheme, uplink transmission and downlink transmission occupy the same frequency band and are performed at different times. The channel response of the TDD scheme is substantially reciprocal. This is because the downlink channel response and the uplink channel response are almost the same in a given frequency domain. Therefore, in the TDD-based wireless communication system, the downlink channel response has an advantage that it can be obtained from the uplink channel response. The TDD scheme can not simultaneously perform downlink transmission by a base station and uplink transmission by a UE because the uplink transmission and the downlink transmission are time-divided in the entire frequency band. In a TDD system in which uplink transmission and downlink transmission are divided into subframe units, uplink transmission and downlink transmission are performed in different subframes.

Hereinafter, the LTE system will be described in more detail.

2 shows a structure of a radio frame according to FDD in 3GPP LTE.

Referring to FIG. 2, a radio frame includes 10 subframes (one subframe), and one subframe includes two slots. The slots in the radio frame are slot numbered from 0 to 19. The time taken for one subframe to be transmitted is called a transmission time interval (TTI). TTI is a scheduling unit for data transmission. For example, the length of one radio frame is 10 ms, the length of one subframe is 1 ms, and the length of one slot may be 0.5 ms.

The structure of the radio frame is merely an example, and the number of subframes included in the radio frame, the number of slots included in the subframe, and the like can be variously changed.

On the other hand, one slot may include a plurality of orthogonal frequency division multiplexing (OFDM) symbols. How many OFDM symbols are included in one slot may vary according to a cyclic prefix (CP).

One slot includes N _RB resource blocks (RBs) in the frequency domain. For example, the number of resource blocks (RBs) in the LTE system, i.e., N _RB , can be any of 6 to 110.

A resource block (RB) is a resource allocation unit, and includes a plurality of subcarriers in one slot. For example, if one slot includes 7 OFDM symbols in the time domain and the resource block includes 12 subcarriers in the frequency domain, one resource block includes 7 占 12 12 resource elements (REs) .

In the 3GPP LTE, a physical channel includes a Physical Downlink Shared Channel (PDSCH), a Physical Uplink Shared Channel (PUSCH), a Physical Downlink Control Channel (PDCCH), a Physical Control Format Indicator Channel (PCFICH) ARQ Indicator Channel) and PUCCH (Physical Uplink Control Channel).

The uplink channel includes a PUSCH, a PUCCH, a sounding reference signal (SRS), and a physical random access channel (PRACH).

3 shows a structure of a downlink sub-frame.

In FIG. 3, seven OFDM symbols are included in one slot, assuming a normal CP.

A DL (downlink) subframe is divided into a control region and a data region in a time domain. The control region includes up to three OFDM symbols preceding the first slot in the subframe, but the number of OFDM symbols included in the control region may be changed. A Physical Downlink Control Channel (PDCCH) and another control channel are allocated to the control region, and a PDSCH is allocated to the data region.

The PCFICH transmitted in the first OFDM symbol of the subframe carries a control format indicator (CFI) regarding the number of OFDM symbols (i.e., the size of the control region) used for transmission of the control channels in the subframe. The wireless device first receives the CFI on the PCFICH and then monitors the PDCCH.

The control information transmitted through the PDCCH is referred to as downlink control information (DCI). The DCI includes a set of transmission power control commands for individual terminals in an arbitrary group, and a resource allocation of the PDSCH / RTI > and / or VoIP (Voice over Internet Protocol).

The base station determines the PDCCH format according to the DCI to be transmitted to the UE, and attaches a CRC (cyclic redundancy check) to the control information. The CRC is masked with a unique radio network temporary identifier (RNTI) according to the owner or use of the PDCCH. If the PDCCH is for a particular UE, the unique identifier of the UE, for example C-RNTI (cell-RNTI), may be masked in the CRC. Alternatively, if the PDCCH is for a paging message, a paging indication identifier, e.g., a paging-RNTI (P-RNTI), may be masked on the CRC. If the PDCCH is a PDCCH for a system information block (SIB), a system information identifier (SI-RNTI) may be masked in the CRC. A random access-RNTI (RA-RNTI) may be masked in the CRC to indicate a random access response that is a response to the transmission of the UE's random access preamble.

In 3GPP LTE, blind decoding is used for PDCCH detection. Blind decoding is a method for checking whether a corresponding PDCCH is a control channel by checking a CRC error by demodulating a desired identifier in a cyclic redundancy check (CRC) of a received PDCCH (referred to as a candidate PDCCH) . The base station determines the PDCCH format according to the DCI to be transmitted to the wireless device, attaches a CRC to the DCI, and masks a unique identifier (RNTI) to the CRC according to the owner or use of the PDCCH.

≪ Discontinuous Reception (DRX) >

We now describe DRX (Discontinuous Reception) in 3GPP LTE.

DRX is a technique for reducing battery consumption of a wireless device by allowing a terminal to monitor a downlink channel discontinuously.

Figure 4 shows an example of a DRX cycle.

The DRX cycle specifies a periodic repetition of On-Duration followed by a possible interval of inactivity. The DRX cycle includes the On-period and the Off-period. The On-interval is a period during which the UE monitors the PDCCH within the DRX cycle.

When DRX is set, the UE monitors the PDCCH only in the On-interval and does not monitor the PDCCH in the Off-interval.

The on-duration timer is used to define the On-interval. The On-interval can be defined as the interval during which the onDuration timer is active. The onDuration timer specifies the number of consecutive PDCCH-subframes at the beginning of the DRX cycle. The PDCCH-subframe indicates a subframe in which the PDCCH is monitored.

In addition to the DRX cycle, the interval over which the PDCCH is monitored can be further defined. The period in which the PDCCH is monitored is collectively referred to as an active time. The active time may include an On-period for periodically monitoring the PDCCH and an interval for monitoring the PDCCH due to the occurrence of an event.

<Carrier aggregation>

We now describe a carrier aggregation (CA) system.

A carrier aggregation system means aggregating a number of component carriers (CCs). This carrier aggregation changed the meaning of existing cells. According to carrier aggregation, a cell may refer to a combination of a downlink component carrier and an uplink component carrier, or a single downlink component carrier.

In the carrier aggregation, a cell may be classified into a primary cell, a secondary cell, and a serving cell. A primary cell refers to a cell operating at a primary frequency. The primary cell is a cell in which the UE performs an initial connection establishment procedure or a connection re-establishment process with a base station, Cell. A secondary cell is a cell operating at a secondary frequency, and once established, an RRC connection is established and used to provide additional radio resources.

As described above, unlike a single carrier system, the carrier aggregation system can support a plurality of element carriers (CC), i.e., a plurality of serving cells.

Such a carrier aggregation system may support cross-carrier scheduling. Cross-carrier scheduling may be performed by assigning a resource allocation of a PDSCH that is transmitted over a different element carrier over a PDCCH that is transmitted over a specific element carrier and / or a resource allocation of elements other than an element carrier that is basically linked with the particular element carrier A scheduling method that can allocate resources of a PUSCH transmitted through a carrier wave.

<IoT (Internet of Things) communication>

Hereinafter, the IoT will be described.

5A shows an example of IoT (Internet of Things) communication.

IoT refers to information exchange between the IoT devices 100 without human interaction through the base station 200 or between the IoT device 100 and the server 700 through the base station 200 . In this way, IoT communication is also referred to as Cellular Internet of Things (CIoT) in that it communicates with a cellular base station.

Such IoT communication is a type of MTC (machine type communication). Therefore, the IoT device may be referred to as an MTC device.

The IoT service is different from the service in the conventional human intervention and may include various categories of services such as tracking, metering, payment, medical service, and remote control. For example, IoT services may include meter readings, level measurements, use of surveillance cameras, inventory reporting of vending machines, and so on.

Since IoT communication has a small amount of data to be transmitted and uplink or downlink data transmission / reception rarely occurs, it is desirable to reduce the cost of the IoT device 100 and reduce battery consumption in accordance with a low data rate. Further, since the IoT device 100 has a feature of low mobility, the IoT device 100 has characteristics that the channel environment hardly changes.

5B is an illustration of cell coverage expansion or augmentation for an IoT device.

In recent years, considering the expansion or the increase of the cell coverage of the base station for the IoT device 100, various techniques for expanding or increasing the cell coverage have been discussed.

However, when the coverage of the cell is expanded or increased, if the base station transmits the downlink channel to the IoT device located in the coverage extension (CE) or coverage enhancement (CE) area, Which is difficult to receive. Similarly, when an IoT device located in the CE region directly transmits an uplink channel, the base station has difficulty in receiving the uplink channel.

To solve this problem, a downlink channel or an uplink channel can be repeatedly transmitted over several subframes. Repeating the uplink / downlink channels on several subframes is referred to as bundle transmission.

5C is an exemplary diagram illustrating an example of transmitting a bundle of downlink channels.

5C, the base station transmits a downlink channel (e.g., PDCCH and / or PDSCH) to several subframes (e.g., N subframes ).

Then, the IoT device or the base station can increase the decoding success rate by receiving a bundle of downlink / uplink channels on several subframes and decoding a part or all of the bundle.

6A and 6B are views showing examples of sub-bands in which IoT devices operate.

As one method for low cost of the IoT device, regardless of the system bandwidth of the cell as shown in FIG. 6A, the IoT device uses a sub-band (sub-band) of, for example, about 1.4 MHz .

At this time, the area of the subband in which the IoT device operates may be located in the central area (for example, six middle PRBs) of the system bandwidth of the cell as shown in FIG. 6A.

Alternatively, as shown in FIG. 6B, a plurality of sub-bands of the IoT device may be used in one sub-frame for intra-sub-frame multiplexing between IoT devices, and other sub-bands may be used between IoT devices. At this time, the majority of IoT devices may use other subbands than the central region of the system band of the cell (e.g., middle six PRBs).

IoT communication operating on such a reduced bandwidth can be called NB (Narrow Band) IoT communication or NB CIoT communication.

FIG. 7 shows an example of time resources that can be used for NB-IoT in M-frame units.

Referring to FIG. 7, a frame that may be used for NB-IoT may be referred to as an M-frame, and the length may be illustratively 60ms. In addition, the subframe that may be used for NB IoT may be referred to as an M-subframe, and the length may be, for example, 6 ms. Thus, an M-frame may include ten M-subframes.

Each M-subframe may include two slots, and each slot may be illustratively 3 ms.

However, unlike that shown in FIG. 6, a slot that can be used for NB IoT may have a length of 2ms, so that the subframe has a length of 4ms and the frame may have a length of 40ms. This will be described in more detail with reference to FIG.

Figure 8 is another example illustrating time and frequency resources that may be used for NB IoT.

Referring to FIG. 8, a physical channel or a physical signal transmitted on a slot in an uplink of an NB-IoT includes N _symb ^UL SC-FDMA symbols in a time domain, N _sc ^UL subcarriers. The uplink physical channels can be divided into a Narrowband Physical Uplink Shared Channel (NPUSCH) and a Narrowband Physical Random Access Channel (NPRACH). In the NB-IoT, the physical signal may be NDMRS (Narrowband DeModulation Reference Signal).

The uplink bandwidth of the N _sc ^UL subcarriers during the T _slot slot in the NB-IoT is as follows.

Subcarrier spacing N _sc ^UL T _slot ? F = 3.75 kHz 48 61440 * T _s Δf = 15 kHz 12 15360 * T _s

In the NB-IoT, each resource element (RE) of the resource grid has k = 0, 쪋, N _sc ^UL -1 indicating time domain and frequency domain, and l = 0, 쪋, N _symb ^UL -1. Can be defined as an index pair (k, l).

In the NB-IoT, downlink physical channels include an NPDSCH (Narrowband Physical Downlink Shared Channel), an NPBCH (Narrowband Physical Broadcast Channel), and a NPDCCH (Narrowband Physical Downlink Control Channel). The downlink physical signals include a narrowband reference signal (NRS), a narrowband synchronization signal (NSS), and a narrowband positioning reference signal (NPRS). The NSS includes a Narrowband primary synchronization signal (NPSS) and a Narrowband secondary synchronization signal (NSSS).

NB-IoT, on the other hand, is a communication scheme for wireless devices using reduced bandwidth (i.e., narrowband) with low-complexity / low-cost. This NB-IoT communication is aimed at enabling many wireless devices to be connected in the reduced bandwidth. Furthermore, NB-IoT communication aims to support a wider cell coverage than cell coverage in existing LTE communication.

On the other hand, the carrier having the reduced bandwidth includes only one PRB when the subcarrier spacing is 15 kHz, as can be seen from Table 1 above. That is, the NB-IoT communication can be performed using only one PRB. Here, it is assumed that the radio device transmits NPSS / NSSS / NPBCH / SIB-NB from the base station, and the PRB to which the radio device is connected to receive it is called an anchor PRB (or an anchor carrier). Meanwhile, the radio device may receive an additional PRB from the base station in addition to the anchor PRB (or anchor carrier wave). Among the additional PRBs, a PRB for which the wireless device does not expect to receive NPSS / NSSS / NPBCH / SIB-NB from the base station may be referred to as a non-anchor PRB (or non-anchor carrier).

<Power Saving>

A general UE performs blind decoding on a PDCCH in an on period according to DRX (Discontinuous Reception). However, the NB-IoT device may not transmit / receive data frequently because of its characteristics. Therefore, it is inefficient to frequently monitor the PDCCH in the on interval according to DRX. To maximize energy efficiency, the NB-IoT device may be able to receive a PDCCH or other downlink signal only after receiving a power save signal (also referred to as a WAK (wake up signal)).

9 is a flowchart showing an example of utilizing a power saving signal (or WUS).

As can be seen with reference to FIG. 9, the base station may transmit a power saving signal (or WUS) before transmitting the PDCCH (or MPDCCH or NPDCCH). Upon receiving the power saving signal (or WUS), the NB-IoT device can monitor the PDCCH (or MPDCCH or NPDCCH).

&Lt; Disclosure of the present invention &

The power saving signal (or WUS) defined in this specification is a signal that indicates whether a base station transmits a corresponding signal or channel or a low payload before transmitting a specific signal or channel intended by the base station For example. The power saving signal (or WUS) may be used for the purpose of reducing power consumption required for monitoring a specific signal or channel. Specifically, when a repetition of a specific signal or channel is performed for an NB-IoT device or an MTC device, instead of monitoring the repeating channel a high number of times each time, the repeater power saving signal (or WUS) So that unnecessary power consumption can be prevented. Or to replace the role of a synchronization signal required for monitoring a particular signal or channel, so as to deliver information while synchronizing on time / frequency within a shorter time. Alternatively, the power saving signal (or WUS) may refer to a period in a time / frequency domain in which a specific signal or channel is transmitted, and may be for reducing overhead required for transmission of the signal or channel.

Hereinafter, the present invention will be described mainly with reference to the NB-IoT, but it is apparent that the description of the power saving signal (or WUS) in this specification can be applied to a general communication system.

I. First Invention

According to the first disclosure, the base station sets an expiration timer of the power saving signal (or WUS) to inform the NB-IoT device. If the NB-IoT device does not receive the power save signal (or WUS) while the power save signal (or WUS) expiration timer is running after acquiring the last power save signal (or WUS) Ignore it and monitor the corresponding channel immediately.

If the NB-IoT device fails to receive a power saving signal (or WUS), it may not be able to monitor it, even if there is a corresponding channel to actually receive. (2) the base station transmits a power save signal (or WUS), but the NB-BS does not transmit the power saving signal (or WUS) due to the scheduling restriction; IoT devices may not be recognized. (1), if it is determined that it is not suitable to operate the power saving signal (or WUS) from a long-term point of view, the base station transmits the power save signal (or WUS) to the NB- IoT devices. Alternatively, the base station may send a message, such as a SIB change notification, to inform it. If the SIB change notification is also notified through the power save signal (or WUS), the scheduling constraint problem will reoccur and can not be a fundamental solution. (2), for example, if the repetition level of the power saving signal (or WUS) transmitted by the base station is not sufficient for the NB-IoT device, the actual power saving signal (or WUS) The probability of receiving it may be reduced. In this case, the NB-IoT device may not receive a corresponding channel for a long time. In both of the above problems, it may happen that the NB-IoT device can not receive the corresponding channel for a long period of time, so that the delay may increase or the normal operation may fail.

In order to solve such a problem in the first disclosure, when the NB-IoT device fails to receive the power saving signal (or WUS) for a predetermined time, the NB-IoT device transmits the power saving signal (or WUS) , And suggests a method for directly monitoring the corresponding channel without monitoring the power saving signal (or WUS). The power save signal (or WUS) expiration timer can inform the base station to the NB-IoT device through the upper layer signals such as SIB or RRC signals.

When using the proposed scheme, the expected benefits are as follows. (1) Since the base station does not need to transmit a separate signal to notify whether the power saving signal (or WUS) is operated, there is an advantage that there is no increase in overhead. (2) If there is a large amount of traffic to be processed by the base station temporarily, it is possible to schedule the channel corresponding to the NB-IoT device without the overhead of transmitting the power saving signal (or WUS). (3) Even when the actual power saving signal (or WUS) is being operated, the detection probability for the corresponding channel of the NB-IoT device can be kept the same.

10 shows an example in which the base station and the NB-IoT device apply an expiration timer.

The maximum time that the NB-IoT device expects the power saving signal (or WUS) may be defined through the expiration timer. The expiration timer may be applied (or driven) from a point in time when transmission / reception of the previous power saving signal (or WUS) starts (or ends). From the viewpoint of the transmitting end (that is, the base station), the expiration timer can be driven from the point at which the power saving signal (or WUS) was last transmitted. If the base station wishes to transmit a corresponding channel after the expiration timer, the transmission of the power saving signal (or WUS) may be omitted and the corresponding channel may be immediately transmitted. From the viewpoint of the receiving end (i.e., the NB-IOT device), it is possible to drive the expiration timer from the time when the power saving signal (or WUS) is last received. And immediately monitor the corresponding channel.

At this time, even when the power saving signal (or WUS) is not actually present, if the NB-IoT device detects an error, the NB-IoT device may stop driving the expiration timer. In order to prevent this, even when the NB-IoT device determines that the power saving signal (or WUS) is present, if the detection of the corresponding channel fails, the expiration timer can be continuously driven.

Alternatively, the time at which the RRC connection is released for the expiration timer may be considered. For example, the base station transmits a downlink control channel (e.g., NPDCCH, MPDCCH, EPDCCH, or PDCCH) or a downlink data channel (e.g., NPDSCH, PDSCH) used for instructing the NB- (E.g., NPUSCH Format 2 or PUCCH) reporting that the NB-IoT device will perform an RRC connection release at the BS or an NB-IoT device, or an uplink data channel (e.g., NPUSCH Format 1, PUSCH May be set as a reference time point at which the expiration timer starts.

Alternatively, an expiration timer may be driven based on a reference time point of an absolute time unit in which the base station operates. For example, an operation time point of the expiration timer can be determined based on a time unit in which the base station and the NB-IoT device can recognize the same system frame number (SFN) or hyper frame number (HFN). As a concrete method, the expiration timer can be expressed in a window form. For example, the window may be defined using SFN and / or HFN. The window is defined by a section that is repeated in units of N subframes consecutively counted from a reference subframe index expressed using a specific SFN and / or HFN (e.g., the first subframe included in SFN = 0) . If a power save signal (or WUS) is detected in a particular window, it can be assumed that the NB-IoT device can also transmit a power save signal (or WUS) in the next expiration timer window. On the other hand, if the power saving signal (or WUS) is not detected in the first window, the NB-IoT device can assume that there is no power saving signal (or WUS) transmission from the next window period.

I-1. Proposition 1 of the first disclosure

If the first initiative approach is used and the NB-IoT device fails to receive a corresponding channel during a power saving signal (or WUS) reconfirmation timer, the NB-IoT device sends a power save signal (or WUS Can be requested to update.

If the NB-IoT device aborts the operation associated with the power-saving signal (or WUS) after the expiration timer, the power consumption of the NB-IoT device may increase compared to before. Therefore, it may be necessary to restart the operation associated with the power save signal (or WUS). In addition, if the repetition level of the power saving signal (or WUS) set by the base station is not sufficient, the NB-IoT device should report its status to the base station and update the configuration of the power saving signal (or WUS) There is a need.

In order to solve the above-described problem, in this section, a reconfirmation timer of the power saving signal (or WUS) is set. When the NB-IoT device does not receive the corresponding channel during the reconfirmation timer, The device proposes a scheme to enable the request to update the information associated with the power saving signal (or WUS). For example, the NB-IoT device may perform the request over an uplink channel such as a RACH. The value of the reconfirmation timer may include a predetermined fixed value, or may include a value implicitly or explicitly set via an upper layer signal.

The reconfirmation timer may be driven at the same time as the expiration timer defined in the first disclosure. Or the revalidation timer may be started from the time point when the expiration timer defined in the first start expires.

I-2. Proposition 2 of the second disclosure

According to proposal 2, if the NB-IoT device fails to receive the corresponding channel during a searching timer for change notification, the NB-IoT device may resume monitoring the power save signal (or WUS) .

If the base station does not want to support the power save signal (or WUS) anymore, it should send a change notification to the NB-IoT device informing the change of the configuration. For example, if the corresponding channel is a paging signal, the base station informs the NB-IoT device of the SIB change notification via the paging signal, and the NB-IoT device re-transmits the SIB for the power save signal (or WUS) It is possible to acquire information on the configuration change of the power saving signal (or WUS). Therefore, if no information about the change notification is provided, the NB-IoT device can assume that the configuration information of the previously acquired power save signal (or WUS) is still valid.

Proposal 2 defines a change notification search timer and proposes a method for resuming monitoring of the power saving signal (or WUS) when the NB-IoT device fails to receive a channel corresponding to this interval do. If proposal 2 of the first initiation is used in conjunction with the first initiation, then the NB-IoT device may restart the expiration timer of the first initiation from the point at which the detection timer of the change notification ends.

The search timer defined in proposal 2 of the first disclosure may be the same as the expiration timer defined in the first disclosure. Alternatively, the search timer of the change notification may be started from the time point when the expiration timer defined in the first start is completed.

II. The second initiative

According to the second disclosure, when the power saving signal (or WUS) is set to be used, the base station can set a skipping occasion of the power saving signal (or WUS) to inform the NB-IoT device. The NB-IoT device can assume that the corresponding channel is transmitted from the base station even if there is no power saving signal (or WUS) at the position of the skip interval.

When the NB-IoT device determines whether to monitor the corresponding channel by using the power saving signal (or WUS), the base station needs to transmit a power saving signal (or WUS) at a timing before the corresponding channel occurs . However, it is impossible to monitor the power saving signal (or WUS) due to (1) the power saving signal (or WUS) is not easily transmitted due to the scheduling restriction, or (2) the power saving signal Or it may be inconvenient.

In order to solve such a problem, a second disclosure proposes a method of setting a period in which a corresponding channel is transmitted without transmitting a power saving signal (or WUS). When the scheme of the second disclosure is used, the NB-IoT device normally monitors the power saving signal (or WUS) and then determines whether to monitor the corresponding channel. However, at the timing specified by the skip interval, WUS) without monitoring the corresponding channel can be monitored immediately.

The skip interval may be set according to any one of the following several options.

(Option 2-1) The NB-IoT device can directly monitor the corresponding channel without monitoring the power saving signal (or WUS) in the SFN (or HFN) sections #N to # (N + T).

(Option 2-2) The NB-IoT device can determine the position of the skip interval based on the time interval corresponding to N times the DRX cycle T of the corresponding channel.

11A and 11B are views illustrating the operation of the NB-IoT device in the skip interval according to Option 2-1 and Option 2-2 of the second disclosure.

Referring to FIG. 11B, the NB-IoT device receives setting information on the power saving signal. The setting information may include setting information for a skip occasion of the power saving signal.

11A and 11B, during the skip interval, the NB-IoT device can monitor the downlink channel or the downlink signal without monitoring the power saving signal.

In the case of the option 2-1, the base station sets a subframe period for skipping the monitoring of the power save signal (or WUS) and informs the NB-IoT device of the related information. In this case, the SFN (or HFN) #N at which the skip operation starts to be applied and the period T to be applied may be included and may be transmitted through an upper layer signal such as an SIB or an RRC signal.

12 is an exemplary diagram illustrating the operation of an NB-IoT device according to option 2-2 of the second disclosure;

In the case of the option 2-2, the base station may determine to inform the NB-IoT device of a separate DRX cycle for skipping the monitoring of the power save signal (or WUS). Where the separate DRX cycle may be expressed as a multiple of the DRX cycle used by the corresponding channel. The multi-valued N may be delivered to the NB-IoT device via an upper layer signal such as an SIB or RRC signal.

For NB-IoT devices to which eDRX is applied, the same applies to the eDRX cycle unit. In this case, a separate DRX cycle can be calculated in units of eDRX. At this time, the skip operation can be applied to (1) only a part of paging occasion (PO) in the paging transmission window (PTW) area in the ON-interval state of the DRX. For example, monitoring of the power saving signal (or WUS) may be skipped for the last paging interval PO in the PTW area. (Or WUS) during all paging occasions of a particular PTW area (2) or a particular PTW area. For example, if an eDRX cycle occurs at a period of Te, a separate eDRX cycle corresponding to the period of N * Te may be set.

If option 2-2 is applied to a cell-specific search space that multiple NB-IoT devices must simultaneously monitor, a separate DRX cycle may operate on a cell-specific DRX cycle basis. For example, if the corresponding channel corresponds to a common search space (CSS) for reading the paging signal, the separate DRX cycle may be defined as a multiple of the cell-specific DRX cycle Tc. In the case of the paging signal, the paging interval corresponding to the skip interval (or the SFN at which the paging starts) can be determined by the following equation.

In the above equation, T _skip means a separate DRX cycle, and T _skip = T _C x N.

III. The third disclosure

According to the third disclosure, when the power saving signal (or WUS) is set to be used, the repetition level applied to the power saving signal (or WUS) may be one or more.

When the NB-IoT device determines whether to monitor the corresponding channel by using the power saving signal (or WUS), the base station needs to transmit a power saving signal (or WUS) at a timing before the corresponding channel occurs . However, when the power saving signal (or WUS) is not easily transmitted due to (1) scheduling restriction, or (2) when the coverage level is poor, the power saving signal (or WUS) Or WUS) may or may not be monitored.

Also, when the power saving signal (or WUS) is used for downlink synchronization, it is necessary to ensure a higher level of repetition level than otherwise. If the power save signal (or WUS) is used for downlink synchronization, the NB-IoT device may skip downlink synchronization by using an external synchronization signal such as PSS / SSS (or NPSS / NSSS) Thus, a power saving gain can be obtained. However, since it is used for downlink synchronization, there is a disadvantage that the number of iterations must be increased. On the other hand, if the power saving signal (or WUS) is not used for downlink synchronization, or if the number of repetition is not sufficient, the NB-IoT device transmits a downlink Motivation must first be met.

Also, a problem that may occur when the repetition level of the power saving signal (or WUS) is determined independently for each cell and the actual repetition level designated for each NB-IoT device are independently present can be considered. The actual repetition level of the power saving signal (or WUS) can be set to be lower than the maximum repetition level set for the particular NB-IoT device (s) with a high received signal strength within the coverage. The NB-IoT device can perform its own power saving signal (or WUS) monitoring based on the actual repeat level determined by the specific conditions. This may be an object of obtaining an overhead reduction effect that reduces resources consumed for transmitting a power saving signal (or WUS) on the base station side. In terms of NB-IoT devices, the power saving signal (or WUS) monitoring area can be saved to maximize power saving. However, if the criteria for determining the actual interval is incomplete, or if the NB-IoT device's coverage status is changed and the required actual repeat level changes, a measure may be needed to prepare for this.

In the third disclosure, it is proposed to set the repetition level of the power saving signal (or WUS) differently according to the power saving signal (or WUS) interval. To do this, the base station must provide the NB-IoT device with different repetition levels and information about the power saving signal (or WUS) interval to which each repetition level is applied. This information can be transmitted to the NB-IoT device by the base station through an upper layer signal such as SIB or RRC signal.

According to the third disclosure, when two repetition levels are used, one repetition level is designated as the basic repetition level, and the remaining repetition levels are defined as additional repetition levels. For example, it can be assumed that the basic repetition level is the cell maximum repetition level, and the additional repetition level is the actual repetition level. Or both the basic repetition level and the additional repetition level may be set to be cell common (or UE specific). The power saving signal (or WUS) period to which the additional repetition level is applied may be set according to one of the following options.

(Option 3-1) The NB-IoT device applies an additional repetition level in the SFN (or HFN) section #N to # (N + T) WUS) can be monitored.

13 is an exemplary diagram illustrating the operation of the NB-IoT device according to Option 3-1 of the third disclosure;

Referring to FIG. 13, in the absence of a corresponding channel, the operation of the NB-IoT device is shown.

In the case of the option 3-1, the base station may determine a subframe period for applying an additional repetition level to the power saving signal (or WUS) and transmit the related information to the NB-IoT device.

The related information may include an SFN (or HFN) #N at which the application of the additional repetition level starts and a period T to be applied, and may be delivered via an upper layer signal such as an SIB or RRC signal.

(Option 3-2) The NB-IoT device can determine where the additional level of repetition is applied to the power saving signal (or WUS) based on the time period corresponding to N times the DRX cycle T of the corresponding channel. In the other sections, the default repetition level is applied.

In the case of the option 3-2, the base station can inform the NB-IoT device of a separate DRX cycle for applying an additional repetition level to the monitoring of the power saving signal (or WUS). In this case, the separate DRX cycle may be represented by a multiple of the DRX cycle used by the corresponding channel. The multi-valued N may be delivered to the NB-IoT device via an upper layer signal such as an SIB or RRC signal.

The option described in option 3-2 above may be applied in units of eDRX cycles for NB-IoT devices to which eDRX is applied. In this case, a separate DRX cycle for applying an additional repetition level to the monitoring of the power saving signal (or WUS) may be calculated in units of eDRX. At this time, the additional repetition level can be applied only to (1) some paging occasions in the paging transmission window (PTW) region within the DRX's on duration. For example, the last paging interval PO in the PTW region may be set to apply a default repetition level (e.g., a maximum repetition level) to the power saving signal (or WUS) monitoring, and an additional repetition level (e.g., . &Lt; / RTI &gt; The additional repetition level may be applied to all paging occasions of the particular PTW region (2). For example, if the eDRX cycle is set to the period of T _e , then normally an additional repetition level (eg, the actual repetition level) is applied and a default repetition level (eg, the maximum repetition level) is applied for each period of N * T _e .

If Option 3-2 is applied to a cell-specific search space that many NB-IoT devices should monitor concurrently, a separate DRX to apply an additional repetition level to the power-saving signal (or WUS) The cycle may operate on a cell specific DRX cycle. For the example, if the corresponding channel is available for the common search space to read the paging message, the power saving signal separate DRX cycle for the application of an additional repeat-level to the monitoring (or WUS) is cell-specific DRX cycle T _c Can be defined as multiple. In the example of the above paging, the paging occasion (or the SFN at which the paging starts) corresponding to the occasion of the power saving signal (or WUS) to which the additional repetition level is applied can be determined by the following equation. In the following equation T _add means a separate DRX cycle for applying an additional repetition level to the monitoring of the power saving signal (or WUS). T _add = T _c x N.

FIG. 14 is an exemplary diagram illustrating the operation of the NB-IoT device according to option 3-2 of the third disclosure; FIG.

Referring to FIG. 14, when there is no corresponding channel, the operation of the NB-IoT device is shown.

On the other hand, in the scheme proposed in the third disclosure, the power saving signal (or WUS) used in the sections where the repetition level of the power saving signal (or WUS) is different may be different from each other. This may be the purpose of (1) adjusting the amount of information that can be expressed using the power saving signal (or WUS) when the repetition level is different, (2) considering the downlink synchronization effect, In the case of the power saving signal (or WUS), the downlink synchronization capability may not be provided, while in the opposite case, the purpose may be to provide the downlink synchronization capability.

IV. Fourth Disclosure

According to the fourth disclosure, the NB-IoT device can determine whether to skip the power saving signal (or WUS) based on its UE_ID, for a corresponding channel of a particular timing.

If the corresponding channel is a common channel that is commonly monitored by a number of NB-IoT devices and the power saving signal (or WUS) is also commonly monitored by a number of NB-IoT devices, When a transmitted power saving signal (or WUS) is transmitted to schedule a channel, it may happen that other NB-IoT devices that do not need a corresponding channel actually perform monitoring of the corresponding channel. In this case, NB-IoT devices that do not need a corresponding channel actually perform unnecessary monitoring, resulting in unnecessary power consumption.

In order to solve such a problem, the fourth aspect proposes a method of determining whether the NB-IoT device monitors the power saving signal (or WUS) based on its identifier (e.g., UE_ID). At this time, the NB-IoT devices sharing the occasion in which the saving signal (or WUS) has the same power can be divided into subgroups based on the identifier (UE_ID). For example, when dividing NB-IoT devices sharing an occasion in which the saving signal (or WUS) has the same power into N _sub subgroups, the NB-IoT device adds N _sub modules to its identifier (UE_ID) Modular operation may be performed to determine whether to monitor a specific power saving signal (or WUS) occasion.

For example, in a case where a skip interval of a power saving signal calculated by an identifier (UE_ID) of a corresponding NB-IoT device is adjacent in a situation where a channel corresponding to a specific NB-IoT device is to be allocated, , The base station can transmit only the corresponding channel without transmitting the power saving signal (or WUS). At this time, since other NB-IoT devices that are monitored in the corresponding occasion can not acquire the power save signal (or WUS), they can monitor the corresponding channel. Therefore, power consumption is reduced. On the other hand, the NB-IoT device requiring the corresponding channel directly monitors the corresponding channel, so that the corresponding channel can be acquired without increasing the missing probability.

15 is an exemplary view showing the operation of the NB-IoT device according to the fourth disclosure;

Fig. 15 shows the operation of the NB-IoT device which requires the corresponding channel and the operation of the NB-IoT device which does not. In FIG. 15, the existing power saving signal operation is an example for the case where the fourth disclosure is not applied, and the subgroup area represents an example where the fourth disclosure is applied.

V. Fifth Disclosure

The NB-IoT device can determine whether to monitor the power saving signal (or WUS) based on its RSRP.

When the base station determines the repetition level of the power saving signal (or WUS), the base station may set the coverage level and the overhead that the base station desires to support. However, if the repetition level of the power saving signal (or WUS) supported by the base station is insufficient for a specific NB-IoT device, the loss probability of the power saving signal (or WUS) may become high. Therefore, the intended target condition may not be satisfied. However, since the base station can not determine the coverage level of an arbitrary NB-IoT device, it may not know whether the NB-IoT device supports the appropriate repeat level. If the repetition level is not suitable, the NB IoT device may fail to receive the corresponding channel.

In the fifth embodiment, a method for determining whether to use the power saving signal (or WUS) based on the RSRP and the threshold value measured by the NB-IoT device is proposed. In this case, the RSRP means a measurement result in which the NB-IoT device can estimate its own coverage level based on signals received from the base station. Therefore, the proposed content can be equally applied to the use of other measures that may have similar effects. If the RSRP measured by the NB-IoT device is above a certain threshold value, the NB-IoT device may decide to perform an operation to monitor the power saving signal (or WUS) to determine whether the corresponding channel is transmitted. In the opposite case, the NB-IoT device can always monitor the corresponding channel regardless of the presence or absence of a power save signal (or WUS) (or without performing a power save signal (or WUS) monitoring).

At this time, the threshold value may be determined depending on the setting information of the power saving signal (or WUS). For example, the threshold value may be determined depending on the repetition level of the power saving signal (or WUS) and / or the transmission power. At this time, the threshold value is defined in the standard so that the base station and the NB-IoT device can make the same assumption, so that the base station and the NB-IoT device can share the threshold value. Alternatively, the threshold values may be individually determined by the implementation of the NB-IoT device.

Or a specific threshold may be set by the base station and delivered to the NB-IoT device. At this time, the threshold value can be set to the NB-IoT device through an upper layer signal such as SIB or RRC signal. Alternatively, the threshold may be dynamically controlled via the DCI of the control channel that the NB-IoT device can acquire before monitoring the power saving signal (or WUS).

(Option 5-1) If the NB-IoT device does not meet the threshold value suitable for monitoring the power save signal (or WUS), the NB-IoT device sends a change to the appropriate power saving signal (or WUS) Can be requested.

In particular, if the RSRP of a particular NB-IoT device does not meet the threshold and is not suitable for monitoring the power saving signal (or WUS), the NB-IoT device sends a power save signal (Or WUS) in order to change the settings. For example, an NB-IoT device may transmit a specific signal or channel to a base station for the purpose of requesting a higher repetition level.

The requested information may be its RSRP value, or it may be a repetition level (and / or power level) suitable for itself. Alternatively, it may report whether the current RSRP satisfies the threshold value simply through 1-bit information.

(Option 5-2) The base station can inform the NB-IoT device of the transmission power of the signal for calculating the RSRP and / or the transmission power of the power saving signal (or WUS).

In order for the NB-IoT device to measure the RSRP and calculate the threshold value, it is necessary to know the transmission power level of the RSRP reference signal.

At this time, RSRP can be measured through a power saving signal (or WUS). At this time, the base station transmits information related to the transmission power of the power saving signal (or WUS) to the NB-IoT device so that the NB-IoT device can accurately measure the RSRP or utilize it in the process of calculating the threshold value You can tell. Where the information may be the magnitude of the absolute transmit power at which the power saving signal (or WUS) is transmitted, or it may be a ratio relative to the transmit power of the other signal (e.g., NRS, CRS, or other channels). If RSRP is measured using the power save signal (or WUS), the base station may periodically transmit a power save signal (or WUS) to the appointed position at all times.

In this case, RSRP can be performed on a channel in which transmission power size information is already transmitted, such as NRS or CRS. At this time, if there is no additional information, the NB-IoT device can use the information of the NRS and / or CRS to determine the threshold value of RSRP or to compare the threshold value with the RSRP value. Or the power offset of the NRS / CRS and the power saving signal (or WUS). This may be used to reflect the influence of the power offset in the calculation of the threshold value or to use it in the process of comparing the threshold value and the RSRP value when the signal for calculating the RSRP is different from the signal for performing the actual desired operation.

VI. 6th initiation

According to the sixth disclosure, the repetition level of the power saving signal (or WUS) may vary with time.

The repetition level promised between the base station and the NB-IoT device may occur when the NB-IoT device moves or is not valid according to the change of the channel environment. To prevent this situation, this section proposes that the repetition level of the power saving signal (or WUS) fluctuates over time.

Specifically, the repetition level can be set to have a higher value after a certain time from the point at which the repetition level was previously determined. This may be the purpose of preparing for cases where the NB-IoT device has a poorer coverage level. The proposed scheme does not cause degradation in performance even if the NB-IoT device maintains the same coverage level or a better coverage level. At this time, a specific time can be defined as a timer. The timer may be set to initialize at the time the last iteration level is determined.

For example, the initial repetition level of an NB-IoT device may be determined using one of the following options, and then a change in repetition level over time may be expected according to a predefined rule. At this time, the determination of the initial repetition level can be determined UE-specific for each NB-IoT device, but it can be determined based on the repetition level commonly set in the cell.

(Option 6-1) Repeat level set for the last NPUSCH transmission performed by the NB-IoT device

(Option 6-2) In the connected mode, the repetition level (for example, the number of repetitions specified by Rmax or DCI) of NPDCCH and / or NPDSCH last received by the NB-IoT device,

(Option 6-3) The final Coverage Enhancement (CE) level at which the NB-IoT device successfully transmitted the random access preamble during the RACH process

(Option 6-4) In the RACH process, the NB-IoT device receives a second message (e.g., Msg2) or a fourth message (e.g., Msg4) is repeatedly set for NPDCCH and / or NPDSCH level

(Option 6-5) For the purpose of setting the initial repetition level, the base station sets the repetition level

The unit in which the repetition level is increased can be calculated on the basis of the absolute time, or the number of available time domain resources. When the point at which the initial repetition level is determined is n0, it is possible to set the repetition level to be higher at the point of n0 + k0. In this case, if the NB-IoT device transmits a signal for determining the coverage level to the base station before k0, the initial repetition level may be set to be reset based on the corresponding signal. In this case, if the unit in which the number of repetitions is increased is an absolute time, the value of k0 can be defined as the number of all slots or subframes regardless of availability, and if the unit in which the repetition increases is an available time domain resource The value of k0 may be determined by the number of slots or subframes through which the power saving signal (or WUS) can be transmitted, such as a valid DL subframe.

Or a unit in which the repetition level is increased can be calculated based on the number of power saving signals (or WUS) occasions. For this purpose, there may be a counter parameter for calculating the number of occurrences of the power saving signal (or WUS) occasion. For example, if the counter parameter is defined as CountPOforRepLevel for the convenience of description, the CountPOforRepLevel value is set to a value at which the NB-IoT device can monitor the first power saving signal (or the first power saving signal WUS) occasion), the value of the initial value may be initialized to zero. Each time thereafter an occasion for a power save signal (or WUS) occurs (or whenever the power save signal (or WUS) monitoring fails), the value of CountPOforRepLevel can be set to increment by one. If the value of CountPOforRepLevel exceeds a predetermined threshold set by a predetermined (or higher) layer signal, the NB-IoT device may expect to increase the repeat level from the occasion of the power save signal (or WUS) thereafter have.

The repetition level can be set to be continuously updated after a specific point in time according to a predetermined rule after the initial repetition level is determined. At this time, the selectable maximum repetition level can be set so as not to exceed the cell-common repetition level.

The NB-IoT device can determine the repetition level to monitor based on RSRP and timing. For example, the NB-IoT device may maintain the repeat level if the measured RSRP size remains unchanged even after a certain time according to the sixth disclosure, or if the RSRP situation is better, Signal (or WUS) can be monitored. On the other hand, if the base station does not know the RSRP status of the NB-IoT device, it determines the repeat level according to the method promised at the sixth start.

VII. Seventh Disclosure

(Or WUS) transmission corresponding to a corresponding channel at a specific time point is abandoned (&quot; WUS &quot;) in a situation where a power saving signal (or WUS) is used to notify whether a corresponding channel is periodically transmitted drop), the corresponding channel at the time point may be monitored by the power save signal (or WUS) at the previous time point.

The power saving signal (or WUS) may not be transmitted by another signal or channel. For example, transmission of a power saving signal (or WUS) may not be possible in a section requiring transmission of a signal or channel having a high priority such as a synchronization signal or a SIB. If the transmission of the signal or channel continues for a long period of time, the transmission of the power saving signal (or WUS) itself may be dropped. In this case, in the case of the NB-IoT device which determines whether to monitor the corresponding channel through the power saving signal (or WUS), the monitoring opportunity of the corresponding channel is lost, and the delay and reliability may be reduced .

In order to solve such a problem, in a case of a corresponding channel in which a corresponding power saving signal (or WUS) is dropped by a simple method, a method of monitoring the power saving signal (or WUS) This can be. In this case, however, there is a disadvantage in that the power saving signal through the power saving signal (or WUS) can not be obtained at the position of the corresponding channel.

In order to solve the above problem, in this section, when transmission of a power saving signal (or WUS) corresponding to a corresponding channel at a specific point in time is dropped, the corresponding channel at the point in time is a power saving signal (Or WUS) may be indicated for monitoring. For example, assuming that the NPDCCH for paging is a channel corresponding to NB-IoT and a paging interval (PO) occurs at a period of T, a power saving signal (or a power saving signal) corresponding to the position of the specific paging interval WUS) overlaps with the SIB transmission position and drops. At this time, whether to monitor the corresponding paging interval PO can be indicated by transmission of the power saving signal (or WUS) corresponding to the preceding paging interval PO. If the power saving signal (or WUS) corresponding to the preceding paging interval PO is instructed not to monitor the corresponding channel, monitoring may not be performed during the corresponding paging interval PO and skipped.

16 is an exemplary diagram illustrating the operation of an NB-IoT device according to the fifth disclosure;

16 shows an example in which, when a power saving signal (or WUS) is dropped at a specific position, the power saving signal (or WUS) at the previous transmission time indicates transmission of two corresponding channels succeeding thereto have.

VIII. Eighth start

In the eighth embodiment, in the case where the power saving signal (or WUS) is used to inform whether or not the corresponding channel to be periodically transmitted is used, the transmission of the corresponding channel corresponding to the power saving signal (or WUS) the power saving signal (or WUS) at that point of time is used to indicate whether to monitor the corresponding channel at the next time point.

In a specific situation, it is possible to transmit the power saving signal (or WUS), but it is impossible to transmit the corresponding channel corresponding thereto. For example, in the case of NB-IoT in the current standard, if the transmission interval of the NPDCCH for paging purposes overlaps with another subsequent search space, the previous NPDCCH transmission is defined to be abandoned. Therefore, when the corresponding channel is abandoned, the transmission of the power saving signal (or WUS) disappears and the unnecessary monitoring or waste of resources may occur in the position of the NB-IoT device.

In order to solve the above problem, when the transmission of the corresponding channel is dropped in a simple method, the NB-IoT device can be set not to expect the transmission of the corresponding power saving signal (or WUS). This has the advantage that the relationship between the power saving signal (or WUS) and the corresponding channel can always be kept unchanged, and power consumption due to monitoring of the power saving signal (or WUS) can be reduced when there is no corresponding channel have. However, there is a disadvantage in that the NB-IoT device has to calculate in advance whether to drop the corresponding channel in the process of analogizing the occasion of the power saving signal (or WUS) There is a disadvantage that the scheduling flexibility is forcibly dropped due to the occasion of the scheduling. There is a disadvantage that the delay for reception of the corresponding channel can be greatly increased, especially when the power saving signal (or WUS) transmission corresponding to the subsequent channel is not available.

In order to solve the above problem, in this section, when transmission of a corresponding channel corresponding to a power save signal (or WUS) at a specific point in time is dropped, the power save signal (or WUS) To indicate whether or not to monitor the corresponding channel of the terminal. For example, suppose that in the NB-IoT, the NPDCCH for paging is a corresponding channel, and a paging interval (PO) occurs at a period of T. FIG. Then, it can be considered that the transmission of the corresponding channel corresponding to the position of the specific paging interval PO is delayed to the SIB transmission position and is overlapped with the subsequent search space for paging purpose. At this time, the power saving signal (or WUS) at that time point can be used for indicating whether to transmit the next NPDCCH for paging purpose. If there is no power saving signal (or WUS) at that location, the NB-IoT device can monitor the power save signal (or WUS) at the next location.

17 is an exemplary view showing the operation of the NB-IoT device according to the eighth embodiment;

FIG. 17 shows an example in which, when a corresponding channel at a specific location is abandoned, the corresponding power saving signal (or WUS) indicates transmission of the corresponding channel succeeding thereto.

IX. Ninth initiation

In the ninth embodiment, in a situation where the power save signal (or WUS) is used to notify whether or not the corresponding channel to be periodically transmitted is monitored, the corresponding channel to which the transmission is instructed by the power save signal (or WUS) , The NB-IoT device presents a method of dropping the monitoring of the subsequent power saving signal (or WUS) when the power saving signal (or WUS) is overlapped with the transmission position of the subsequent power saving signal (or WUS). At this time, the NB-IoT device can perform monitoring of the corresponding channel corresponding to the abandoned power save signal (or WUS).

The corresponding channel directed to be monitored by the power save signal (or WUS) may be delayed for transmission purposes to ensure transmission of another signal or channel. For example, in the case of NB-IoT, the NPDCCH transmission for paging purposes may be postponed if the NPDSCH transmission for SI purposes is present. In this case, the NPDCCH transmission position for the paging purpose may overlap with the transmission position of the subsequent power saving signal (or WUS). In such a case, the NB-IoT device can be set to preferentially perform NPDCCH monitoring for paging purposes. However, in this case, the subsequent power saving signal (or WUS) transmission is not guaranteed, and the base station can not instruct the NB-IoT device whether or not the NPDCCH for subsequent paging is transmitted.

In order to solve the above problem, in this section, if a power save signal (or WUS) at a specific point in time instructs transmission of a corresponding channel, a corresponding save channel (WUS) The NB-IoT device monitors the monitoring of the paging NPDCCH corresponding to the discarded power save signal (or WUS) to the power save signal (or WUS) in the case where the transmission of the power saving signal WUS) without any instruction.

18 is an exemplary view showing the operation of the NB-IoT device according to the ninth embodiment;

FIG. 18 shows a scheme for allowing monitoring of a corresponding channel corresponding to a power saving signal (or WUS) at a specific time point if the previous corresponding time slot is abandoned.

X. 10th initiation

In a situation where the power saving signal (or WUS) is used to notify whether a corresponding channel to be periodically transmitted is monitored, a corresponding channel whose transmission is instructed by a power saving signal (or WUS) When superimposing the transmission position of the saving signal (or WUS), the tenth initiation provides a way for the NB-IoT device to postpone the monitoring position of the power saving signal (or WUS) following. The criterion to which the smoke is applied may be limited to the case where the number of transmittable subframes of the power saving signal (or WUS) is sufficient.

A corresponding channel directed to monitor by a power save signal (or WUS) may be delayed for transmission purposes to ensure transmission of another signal or channel. For example, in the case of NB-IoT, NPDCCH transmission for paging purpose can be postponed if there is NPDSCH transmission for SI purpose. In this case, the NPDCCH transmission position for the paging purpose may overlap with the transmission position of the subsequent power saving signal (or WUS). In such a case, the NB-IoT device can be set to preferentially perform NPDCCH monitoring for paging purposes. However, in this case, the subsequent power saving signal (or WUS) transmission is not guaranteed, and the base station can not instruct the NB-IoT device whether or not the NPDCCH for subsequent paging is transmitted.

In order to solve the above problem, in this section, if a power saving signal (or WUS) at a specific time point indicates a transmission of a corresponding channel, a power saving signal (or WUS) The transmission of the power saving signal (or WUS) is delayed.

The proposed scheme is applied only when the transmission length of the power saving signal (or WUS) is sufficiently guaranteed at the position where the power saving signal (or WUS) is delayed. Otherwise, the power saving signal (or WUS) Can be determined. At this time, the transmission length of the reference power saving signal (or WUS) is the maximum power saving signal (or WUS) length set by the base station, or the maximum power saving signal (or WUS) length multiplied by a specific scaling value . At this time, the number of subframes to which the power save signal (or WUS) can be transmitted is determined based on a period from a subframe position where transmission is started after the power save signal (or WUS) is delayed to a corresponding predetermined channel Can be calculated.

19 is an exemplary view showing the operation of the NB-IoT device according to the tenth embodiment;

19 shows an example in which the power save signal (or WUS) at a specific time point is delayed by transmission of the corresponding channel at the previous time point.

XI. Eleventh disclosure

There may be a plurality of transmission positions of the power saving signal (or WUS) in order to notify whether or not a corresponding channel is monitored from the viewpoint of the base station. However, the NB-IoT device may determine one location to monitor the power saving signal (or WUS) according to its capability. In this case, when the NB-IoT device is unsuitable for transmission of the power saving signal (or WUS) at the transmission position determined by the NB-IoT device, the NB-IoT device reselects the proper transmission position and monitors the power saving signal Can be determined.

The base station can support the power saving signal (or WUS) and the relative position of the corresponding channel according to the performance and operation method of various NB-IoT devices. For example, a case where the transmission position of the power saving signal (or WUS) can be determined according to whether the NB-IoT device uses the eDRX mode or not and the gap capability of the NB-IoT device can be determined . To support a power saving signal (or WUS) related operation to the requirements of these various NB-IoT devices, the base station may support one or more power save signal (or WUS) transmission locations for one corresponding channel . For example, the NB-IoT device can select one of the gap sizes between the corresponding power saving signal (or WUS) and the corresponding channel set by the base station based on the eDRX mode and the gap capability have.

However, the transmission location of the selected power save signal (or WUS) may not be appropriate in certain situations. For example, when the transmission position of the power saving signal (or WUS) overlaps with the transmission position of a relatively high priority signal or channel such as SIB transmission, the transmission of the power saving signal (or WUS) More than a certain percentage can be abandoned. In this case, the power saving signal (or WUS) is used to limit the monitoring of the corresponding channel.

In order to overcome the above problems, this section proposes a method for the NB-IoT device to select and monitor the power saving signal (or WUS) transmission position suitable for transmission among the plurality of power saving signal (or WUS) transmission positions. At this time, the transmission position of the power saving signal (or WUS) suitable for transmission means that the transmission of the power saving signal (or WUS) is X% or more (or Y subframe and / or Z number of PRB ) Transmission is possible. If a power save signal (or WUS) corresponding to an existing rule (for example, whether or not the eDRX mode is operated and the selection rule according to the gap capability of the NB-IOT device) is set at a position suitable for transmission of the power saving signal (or WUS) ) If the transmission location is included, the NB-IoT device shall prioritize the selection. If the transmission position of the power saving signal (or WUS) conforming to the existing rule is not included in the position suitable for the transmission of the power saving signal (or WUS), the NB-IoT device will (1) (2) to select a transmission position of the nearest power save signal (or WUS), or to select a transmission position of the power save signal (or WUS) that is closer to the corresponding channel than the transmission position of the power saving signal WUS) to be selected.

20 is an exemplary view showing the operation of the NB-IoT device according to the eleventh disclosure;

In the example shown in FIG. 20, it is assumed that the NB-IoT device has the capability of gap 1. At this time, the NB-IoT device sets a monitoring position of the power saving signal (or WUS) with priority given to the position of the power saving signal (or WUS) at which the transmission position is determined by the gap 1, and otherwise selects the gap 2 as the lane . If both Gap 1 and Gap 2 are not suitable for transmission, the NB-IoT device may operate according to the scheme according to any one of the seventh to tenth aspects of the present invention.

The embodiments of the present invention described above can be implemented by various means. For example, embodiments of the present invention may be implemented by hardware, firmware, software, or a combination thereof. More specifically, it will be described with reference to the drawings.

21 is a block diagram illustrating a wireless device and a base station in which the present disclosure is implemented.

Referring to FIG. 21, the wireless device 100 and the base station 200 may implement the disclosure herein.

The illustrated wireless device 100 includes a processor 101, a memory 102, and a transceiver 103. Similarly, illustrated base station 200 includes a processor 201, a memory 202, and a transceiver 203. The processors 101 and 201, the memories 102 and 202 and the transceivers 103 and 203 may be implemented as separate chips, or at least two blocks / functions may be implemented through one chip.

The transceivers 103 and 203 include a transmitter and a receiver. When a specific operation is performed, only the operation of either the transmitter or the receiver may be performed, or both the transmitter and the receiver operations may be performed. The transceivers 103 and 203 may include one or more antennas for transmitting and / or receiving wireless signals. In addition, the transceivers 103 and 203 may include an amplifier for amplifying a reception signal and / or a transmission signal, and a band-pass filter for transmission on a specific frequency band.

The processor 101, 201 may implement the functions, processes and / or methods suggested herein. The processors 101 and 201 may include an encoder and a decoder. For example, the processor 101, 202 may perform an operation in accordance with the above description. These processors 101 and 201 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, data processing devices, and / or converters that interconvert baseband signals and radio signals.

The memory 102, 202 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage media, and / or other storage devices.

22 is a detailed block diagram of the transceiver of the wireless device shown in Fig.

Referring to FIG. 22, the transceiver 110 includes a transmitter 111 and a receiver 112. The transmitter 111 includes a Discrete Fourier Transform (DFT) unit 1111, a subcarrier mapper 1112, an IFFT unit 1113, a CP insertion unit 11144, and a radio transmission unit 1115. The transmitter 111 may further include a modulator. The apparatus may further include a scramble unit, a modulation mapper, a layer mapper, and a layer permutator, for example. Which may be arranged in advance of the DFT unit 1111. That is, in order to prevent an increase in peak-to-average power ratio (PAPR), the transmitter 111 first passes information through a DFT 1111 before mapping a signal to a subcarrier. A signal spreading (or precoded in the same sense) by the DFT unit 1111 is subcarrier-mapped through the subcarrier mapper 1112 and then transmitted through an IFFT (Inverse Fast Fourier Transform) unit 1113, Signal.

The DFT unit 1111 performs DFT on the input symbols to output complex-valued symbols. For example, when Ntx symbols are input (where Ntx is a natural number), the DFT size (size) is Ntx. The DFT unit 1111 may be referred to as a transform precoder. The subcarrier mapper 1112 maps the complex symbols to subcarriers in the frequency domain. The complex symbols may be mapped to resource elements corresponding to resource blocks allocated for data transmission. The subcarrier mapper 1112 may be referred to as a resource element mapper. The IFFT unit 1113 performs IFFT on the input symbol and outputs a baseband signal for data, which is a time domain signal. The CP inserting unit 1114 copies a part of the rear part of the base band signal for data and inserts it in the front part of the base band signal for data. Inter-symbol interference (ISI) and inter-carrier interference (ICI) are prevented through CP insertion, and orthogonality can be maintained in a multi-path channel.

On the other hand, the receiver 112 includes a radio receiving unit 1121, a CP removing unit 1122, an FFT unit 1123, and an equalizing unit 1124. The wireless receiving unit 1121, the CP removing unit 1122 and the FFT unit 1123 of the receiver 112 are connected to the wireless transmitting unit 1115, the CP inserting unit 1114, the IFF unit 1113, . The receiver 112 may further include a demodulator.

Claims (15)

A method for a wireless device to monitor a downlink channel or a downlink signal, Receiving setting information for a power saving signal; The power save signal is used to indicate that the downlink channel or the downlink signal should be monitored in succession, Wherein the setting information includes setting information for a skip occasion of the power saving signal; Monitoring the downlink channel or the downlink signal without monitoring the power saving signal during the skip interval, Wherein at least one of a length and a position of the skip interval is determined by setting information of a DRX (Discontinuous Reception) cycle. The method according to claim 1, Wherein at least one of the length and position of the skip interval is determined based on N times the length of the DRX cycle. The method of claim 1, wherein the length of the skip interval is (SFN) &lt; / RTI &gt; The method of claim 1, wherein the setting information for the power saving signal And information about an expiration timer. 5. The method of claim 4, Further comprising the step of driving the expiration timer in an interval other than the skip interval. 6. The method of claim 5, Further comprising the step of monitoring the downlink channel or the downlink signal in a case where the power saving signal is not received until the expiration timer expires in a section other than the skip section . 6. The method of claim 5, wherein the expiration timer Characterized in that it is disclosed in connection with the release of a radio resource control (RRC) connection. 8. The method of claim 7, Wherein release of the RRC connection is performed based on reception of a downlink control channel or a downlink data channel. 8. The method of claim 7, Wherein release of the RRC connection is performed based on transmission of an uplink control channel or an uplink data channel. 6. The method of claim 5, wherein the expiration timer Lt; RTI ID = 0.0 &gt; SFN. &Lt; / RTI &gt; A radio apparatus for monitoring a downlink channel or a downlink signal, A transmission / reception unit; And And a processor for controlling said transceiver to receive setting information for a power saving signal, The power save signal is used to indicate that the downlink channel or the downlink signal should be monitored in succession, Wherein the setting information includes setting information for a skip occasion of the power saving signal; Wherein the processor monitors the downlink channel or downlink signal during the skip interval, without monitoring the power saving signal, Wherein at least one of the length and the position of the skip interval is determined by setting information of a discontinuous reception (DRX) cycle. 12. The method of claim 11, Wherein at least one of the length and position of the skip interval is determined based on N times the length of the DRX cycle. 12. The method of claim 11, wherein the length of the skip interval is (SFN) &lt; / RTI &gt; 12. The method of claim 11, wherein the setting information for the power saving signal And an expiration timer. 6. The method of claim 5, Further comprising the step of driving the expiration timer in an interval other than the skip interval.

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